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Biomedical subjects

X X Wang

Publications and source records attributed to X X Wang.

At least 19 recordsLinked to original sources
PubMed2006

Homocysteine accelerates senescence and reduces proliferation of endothelial progenitor cells.

Our previous studies showed that homocysteine (Hcy) reduces endothelial progenitor cell (EPC) numbers and impairs functional activity. However, the mechanisms by which Hcy reduces EPCs numbers and activity remain to be determined. Recent studies have demonstrated that reduced EPCs numbers and activity was associated with EPCs senescence which involved telomerase activity. Therefore, we investigated whether Hcy accelerates the onset of EPCs senescence through telomerase inactivation, leading to cellular dysfunction. EPCs were isolated from peripheral blood and characterized. After ex vivo cultivation, EPCs became senescent as determined by acidic beta-galactosidase staining. Hcy dose-dependently accelerated the onset of EPCs senescence in culture. Moreover, Hcy decreased proliferation of EPCs as assessed by BrdU incorporation assay and colony-forming capacity. To get further insights into the underlying mechanisms of these effects induced by Hcy, we measured telomerase activity and determined the phosphorylation of Akt by using western blot. Hcy significantly diminished telomerase activity and Akt phosphorylation. Taken together, the results of the present study demonstrated that Hcy accelerated the onset of EPCs senescence, leading to cellular dysfunction. The effect of Hcy might be dependent on telomerase inactivation, and Akt dephosphorylation also appeared to play a major role. In addition, atorvastatin had a preventative effect against Hcy-induced EPCs senescence.

Blotting, Western↗
PubMed2006

Kernel classifier construction using orthogonal forward selection and boosting with Fisher ratio class separability measure.

A greedy technique is proposed to construct parsimonious kernel classifiers using the orthogonal forward selection method and boosting based on Fisher ratio for class separability measure. Unlike most kernel classification methods, which restrict kernel means to the training input data and use a fixed common variance for all the kernel terms, the proposed technique can tune both the mean vector and diagonal covariance matrix of individual kernel by incrementally maximizing Fisher ratio for class separability measure. An efficient weighted optimization method is developed based on boosting to append kernels one by one in an orthogonal forward selection procedure. Experimental results obtained using this construction technique demonstrate that it offers a viable alternative to the existing state-of-the-art kernel modeling methods for constructing sparse Gaussian radial basis function network classifiers that generalize well.

Algorithms↗
PubMed2004

Effects of homocysteine on number and activity of endothelial progenitor cells from peripheral blood.

The aim of this study is to investigate whether homocysteine (Hcy) has influences on endothelial progenitor cells (EPCs) number and activity. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 d cultured, attached cells were stimulated with Hcy (to make a series of final concentrations: 10, 50, 100 and 200 micromol/l) or vehicle control for the respective time points (6, 12, 24 and 48 h). EPCs were characterized as adherent cells double positive for DiLDL uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating those on fibronectin-coated dishes, and then adherent cells were counted. Incubation of isolated human MNCs with Hcy dose and time dependently decreased the number of EPCs, maximum at 200 micromol/l, 24 h (approximately 50% reduction, P < 0.01). In addition, Hcy dose and time dependently impaired EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity. In conclusion, hyperHcy may induce the reduction of EPCs with decreased functional activity.

Cell Division↗
PubMed2001

A comparative study of in vitro apatite deposition on heat-, H(2)O(2)-, and NaOH-treated titanium surfaces.

Commercially pure titanium specimens are subjected to three different treatments, and their bioactivity are evaluated by immersing the specimens in a simulated body fluid (SBF, Kokubo's recipe) for various periods up to 7 days, with particular attention being paid to the differences in apatite deposition between surfaces open to SBF and surfaces in contact with the container's bottom. The treatment with a H(2)O(2)/HCl solution at 80 degrees C for 30 min followed by heating at 400 degrees C for 1 h produces an anatase titania gel layer on the specimen surface. This gel layer deposits apatite both on the contact and on open surfaces, and apatite deposition ability does not change with pre-staking in distilled water. The treatment with a NaOH solution at 60 degrees C for 3 days produces a sodium titanate gel layer. This gel layer can deposit apatite only on the contact surface, and the apatite deposition ability is completely lost after 1 day of pre-staking in distilled water. It is concluded, therefore, that the bioactivity of the titania gel originates from the favorable structure of the gel itself while the bioactivity of the sodium titanate gel depends heavily on ion release from the gel. The third treatment, a simple heat treatment at 400 degrees C for 1 h, produces a dense (not porous) oxide layer on the specimen surface. The specimens can deposit apatite on the contact surface after only 3 days of staking in SBF, but they cannot deposit apatite on the open surface for up to 2 months of staking. The implications of such apatite deposition behavior have been discussed in relation to the environments of titanium implants in bone as well as to the methodology of the SBF staking experiment.

Apatites↗
PubMed2001

Cooperative effects of exercise training and genistein administration on bone mass in ovariectomized mice.

We reported that genistein, a soybean isoflavone, prevents bone loss caused by estrogen deficiency, without undesirable effects on the uterus. In this study, we examined cooperative effects of genistein administration and running exercise on bone mass in ovariectomized (OVX) mice. Female mice aged 7 weeks were either sham-operated or OVX and divided into six groups: (1) sham; (2) OVX; (3) OVX, treated with genistein at a submaximal dose (0.4 mg/day) subcutaneously (G); (4) OVX, exercised on a treadmill daily for 30 minutes/day at 12 m/minute on a 10 degree uphill slope (Ex); (5) OVX, given genistein and exercised (ExG); and (6) OVX, treated with 17beta-estradiol (0.03 microg/day) in the same manner as genistein (E2). Four weeks after intervention, bone mass was estimated by dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Bone mineral density (BMD) of the whole femur measured by DXA was higher in both the G and the Ex groups than in the OVX group. Furthermore, BMD in the ExG group was significantly higher than that in the groups receiving either intervention alone. Bone area in distal region of the femur was significantly higher in Ex and ExG groups as compared with those in the OVX and G groups. pQCT analysis showed that the cross-sectional areas (CSAs) and periosteum perimeter at midshaft of the femur did not differ in the sham and OVX groups but were significantly higher in Ex and ExG groups. Histomorphometric analysis showed that bone formation rate/bone surface (BFR/BS) was significantly higher in both Ex and ExG groups as compared with that in non-exercised groups. The bone volume (BV/TV) in the distal femoral cancellous bone was lower in the OVX than that in the sham group, and it was restored completely in the ExG group, as in the E2 group. Thickness of the trabecular bone (Tb.Th) was higher in Ex and ExG groups than that in the OVX and G groups. These results indicate that the combined intervention of moderate exercise and the submaximal dose of genistein administration show a cooperative effect in preventing bone loss in OVX mice.

Animals↗
PubMed2001

[Studies of the correlation between fragile sites and giant panda's breeding problem].

An unique culture system has been established which can effectively indicate fragile sites induced by BrdU on giant panda chromosomes. After we cultured the lymphocytes of giant panda for 96 hours and treated it with low concentration of BrdU (10 micrograms/ml) for only a short time (4 hours), the areas of high-frequency-expressed fragile sites were successfully located on the centromeres of No. 2 and No. 12 chromosomes. After statistic analysis, we found that the frequency of fragile sites on No. 2 and No. 12 chromosomes are notably different among pandas. What is more important, the former is relative to giant pandas' breeding conditions and correlation coefficiency (r equals to -0.772). The result indicates that high frequency of fragile sites on No. 2 chromosome is unfavorable to giant panda's breeding and survival of filial generation.

Animals↗
PubMed2001

[Experimental study on bioglass application in extending alveolar bone crest in rabbit].

OBJECTIVE: To observe the effect of Bioglass guiding bone regeneration and forming normal new bone in extending alveolar bone crest by surgery. METHODS: Thirty-six rabbits were randomly divided into three groups. The first group was treated with Bioglass and the second with hudroxyapectite (HA). The third group was control group. At 4 8 12 weeks after surgery, the condition of bone regeneration was observed with radiological and pathological methods. RESULTS: Statistical analysis showed that there was a significant difference between the third group and the other two groups (P<0.05). In addition, Bioglass can guide bone regeneration faster than hydroxyapatite, and it can be substituted by new bone to form completely normal bone. CONCLUSION: Since Bioglass is more effective than HA in guiding bone regeneration, it is an ideal bone graft substitute.

English Abstract↗
PubMed2000

Improvement of bioactivity of H(2)O(2)/TaCl(5)-treated titanium after subsequent heat treatments.

Commercially pure titanium was treated with a H(2) O(2)/3mM TaCl(5) solution at 80 degrees C for various periods and a titania gel layer was formed on the surface. This gel remained amorphous when heating for 1 h below 200 degrees C and transformed to anatase after heating between 300 degrees and 600 degrees C. The anatase titania gel layers were found to be bioactive as to deposit carbonate ion-incorporated apatite within 1 day of immersion in the Kokubo solution, whereas the amorphous layers did not deposit apatite within 7 days. The apatite particles were found to nucleate preferentially inside the cracks prevailing in the thicker gel layers of 1-h chemically treated specimens. After immersing for 2 days, the titanium specimens were almost completely covered by apatite. Elimination of peroxide radicals from the titania gel and formation of anatase upon subsequent heating are considered to be responsible for the enhanced ability of apatite deposition.

Apatites↗
PubMed2000

[Different evolution rule of SRY gene between hominoid and Old World monkey].

The complete SRY gene of P. nemaeus and M. arctiodes were amplified by using PCR and sequenced. Combined with the same regions of other primate animals, sequence analysis confirmed the conservation of HMGbox. In molecular phylogenetic tree constructed, we made the Ka/Ks value pairwise comparison of HMGbox flanking sequences both intra- and inter- Hominoid and the Old World monkey. To our interest, the pairwise comparison of species in Hominoid suggested a higher Ka/Ks ratio than that in the Old World monkey or between the Old World monkey and marmoset, which showed existent of different pattern of evolution. In addition, in Hominoid Ka/Ks ratio for HMGbox sequences was obviously on the increase. The rate of nonsynonymous substitutions per nonsynonymous site is faster than that of synonymous substitutions per synonymous site in Hominoid (driven by positive directional selection). Our analysis suggested that it might be resulted from functional change of this gene and the system error or the close relationship among Hominoid species. It is also supposed that the positive selection was functioned at the beginning of the divergence of Hominoid species.

Animals↗
PubMed2000

[Study on the coagulation state of sudden deafness].

OBJECTIVE: To explore the coagulation, anticoagulation and fibrinolyic activity in sudden deafness (SD). METHOD: The plasma samples from 42 patients with SD before treatment, 23 patients after treatment and 32 normal controls were examined for coagulation factors, anticoagulation, fibrinolyic activity and platelet functions. RESULT: The functions of coagulation and platelet enhanced, the functions of anticoagulation and fibrinolyic system decreased in 42 patients with SD before treatment. We treated with vitamin, dextranum, energetic compound, vasodialator, antiviral ect in 23 patients for a month. The functions of coagulation, anticoagulation and platelet were no significant difference between the after treatment group and control group (P > 0.05). The level of D-dimer obviously elevated (P < 0.01). CONCLUSION: The functions of coagulation and platelet enhanced, the functions of anticoagulation and fibrinolyic system decreased in SD before treatment, The secondary fibrinolyic activity enhanced after treatment. The thrombosis is one of important pathogenesis of SD.

Adolescent↗
PubMed1998

Modulation of multidrug resistance by taxuspine C and other taxoids from Japanese yew.

Taxuspine C (1), a new taxoid from the Japanese yew Taxus cuspidata, increasing the cellular accumulation of vincristine (VCR) in multidrug-resistant tumor cells as potent as verapamil enhanced the chemotherapeutic effect of VCR in P388/VCR-bearing mice. When taxuspine C (1) was given i.p. daily at 200 mg/kg with 0.2 mg/kg VCR for 5 days, a treated/control (T/C) value of 138% was obtained. The other new taxoids, taxezopidines G (8) and H (9), from the yew also increased the VCR accumulation as potent as verapamil. These results suggest that some taxoids may be useful for overcoming multidrug resistance in tumor cells.

Animals↗
PubMed1997

Prominent role of intracellular Ca2+ release in hypoxic vasoconstriction of canine pulmonary artery.

The possible role of sarcoplasmic reticulum (SR) Ca2+ stores in hypoxic pulmonary vasoconstriction (HPV) is not well understood. In order to assess the possible role of intracellular Ca2+ release from SR Ca2+ stores in HPV, we examined the effects of: (1) ryanodine (10 microM) depletion of intracellular Ca2+ stores, and (2) thapsigargin (THAPS, 2 microM) or cyclopiazonic acid (CPA, 10 microM) depletion of intracellular Ca2+ stores on HPV in canine pulmonary artery. 2 Isometric tension was measured from arterial ring suspended in Krebs-Henseliet solution (K-H) bubbled with 95%O2/5%CO2. Hypoxia was induced by bubbling phenylephrine (PE, 1 microM) precontracted rings with 95%N2/5%CO2. HPV was observed in both intact and endothelial-denuded arteries and expressed as % of maximal KCl contraction (% Tkmax) = 21.3 +/- 3.2%; n = 13 and 21.7 +/- 4%; n = 4 respectively. 3 When SR caffeine sensitive Ca2+ stores were depleted by pretreatment with ryanodine and brief caffeine (15 mM) exposure, the hypoxic response was significantly reduced to 19.1 +/- 9.2% of the control hypoxic contraction (n = 7; p < 0.001) with little or no effect on PE or KCl contractions. On the other hand, in normoxic rings pretreated with THAPS or CPA, the PE responses were significantly reduced (% Tkmax = 18.2 +/- 3.1% compared to 39.0 +/- 3.9% in control; n = 16; P < 0.001; %Tkmax = 3.4 +/- 1.6% compared to 49.9 +/- 7.9% in control; n = 6; P < 0.001; respectively) with no significant effect on caffeine-induced contractions, suggesting that both THAPS and CPA preferentially deplete InsP3-sensitive Ca2+ stores, without affecting the caffeine-sensitive Ca2+ store; consistent with the existence of separate and independent InsP3 and caffeine-sensitive Ca2+ stores in this preparation. 4 When hypoxia was induced in the presence of THAPS or CPA, developed tension was significantly larger than control (% Tkmax = 64.5 +/- 6.0%; n = 16; P < 0.05%; %Tkmax = 78.2 +/- 15%; n = 6; P < 0.05; respectively), was partially blocked by nisoldipine (10 microM) and ryanodine (% Tkmax = 20.3 +/- 3.7%; n = 6), and nearly completely blocked by SK&F 96365 (50 microM). However, the actions of SK&F 96365 appeared to be nonselective since this compound also significantly reduced contractions elicited by KCl, PE and caffeine. 5 Finally, evidence was obtained suggesting: (a) that at least some of the Ca2+ released from the caffeine- and ryanodine-sensitive Ca2+ stores by hypoxia may be taken up and buffered by the InsP3-sensitive Ca2+ stores, and (b) the apparent dependence of HPV on extracellular Ca2+ entry pathways may be partially due to the dependence of the Ca2+ content of intracellular SR Ca2+ stores on sarcolemmal Ca2+ entry pathways. 6 These data suggest that caffeine- and ryanodine-sensitive SR Ca2+ stores contribute significantly to HPV under normal conditions and, in the presence of THAPS or CPA, an additional nisoldipine- and ryanodine-insensitive Ca2+ entry pathway is evoked by hypoxia.

Animals↗
PubMed1997

Liver involvement in epidemic haemorrhagic fever: in situ hybridization, immunohistochemical and pathological studies.

In the present study, liver biopsy specimens from 37 patients with epidemic haemorrhagic fever (EHF) were investigated by using light and electron microscopy, immunohistochemistry for the EHF virus envelope protein G2 and in situ hybridization (ISH) for EHF viral RNA. Immunostaining and in situ hybridization were both positive, and a few of the aetiological agents, the EHF virus (EHFV) particles, were found individually within the dilated Golgi cisternae and vesicles, and the dilated rough endoplasmic reticulum of the hepatocyte. The pathological alterations of the liver cells infected with EHFV were: hepatocellular degeneration, cytoplasmic vacuolation, and spotty necrosis; moreover, zonal necrosis was present and adjacent to the narrowed and occluded sinusoids. In degenerated and spotty necrotic cells, the positive signals from of ISH for EHFV RNA and those from immunostaining for the virus protein were both stronger than those in the zonal liver cell necrosis area. The results showed that hepatocellular degeneration and spotty necrosis might be directly related to the virus and its duplication inside the liver cells, while the zonal necrosis was ischaemic and thought to be caused by microcirculation dysfunction.

Adolescent↗
PubMed1997

Effects of oren-gedoku-to and unsei-in, Chinese traditional medicines, on interleukin-8 and superoxide dismutase in rats.

This study was conducted to elucidate the mechanisms of action of two Chinese traditional drugs, Oren-gedoku-to and Unsei-in, which have been used for many years in the treatment of inflammatory disorders. In rats with acetic acid-induced inflammation, both drugs reduced interleukin-8 concentrations in the serum. Neither drug significantly affected superoxide dismutase activity in the serum, although Unsei-in increased superoxide dismutase activity in liver after 1 month of administration. Oren-gedoku-to showed no significant effect on liver superoxide dismutase activity. It was considered that these medicines exert their anti-inflammatory effects mainly on the early stages of inflammation, wherein increased capillary permeability and migration of leucocytes occur.

Animals↗
PubMed1997

The anti-inflammatory effects of ketoprofen in animal experiments.

The authors investigated the anti-inflammatory actions of ketoprofen using a battery of tests: in the rat paw oedema test induced by five different inciters, in the capillary permeability test, and in measuring the interleukin-8 (IL-8) production and superoxide dismutase (SOD) activity. The findings in these studies show that ketoprofen inhibits rat paw oedema, suppresses capillary permeability, reduces IL-8 production and increases SOD activity in the acetic-acid-induced inflammatory state. These results would seem to provide a clear rationale for exploring the usefulness of ketoprofen in the treatment of acute and chronic inflammatory diseases.

Acetic Acid↗
PubMed1996

Heparan sulfate-dependent and low density lipoprotein receptor-related protein-dependent catabolic pathways for lipoprotein lipase in mouse embryonic fibroblasts.

Heparan sulfate and low density lipoprotein receptor related protein (LRP) have been shown to participate in the uptake and degradation of the enzyme lipoprotein lipase (LPL). Yet, the contribution of each of these pathways to LPL metabolism and their possible dependence is unknown. In the present study we examined the metabolism of 125I-labeled LPL in untreated and heparinase-treated primary wild-type mouse embryonic fibroblasts (MEF) and in mouse fibroblasts that express single LRP allele (PEA-10) or are lacking the LRP (PEA-13). The degradation of LPL in PEA-13 cells was 30% lower than in MEF and PEA-10 cells. Heparinase treatment decreased the LPL degradation by 58%, 79% and 92%, whereas heparin reduced such degradation by 87%, 90% and 94% in MEF, PEA-10 and PEA-13 cultures, respectively. Assuming that a) heparinase treatment abolished the heparan-sulfate pathway, and that b) the degradation remaining in heparin-treated cultures represents nonspecific values, it appears that heparan sulfate contributes about 61%, 83% and 95% of total LPL degradation, whereas the LRP pathway contributes 39%, 17% and less than 5% of LPL degradation in MEF, PEA-10 and PEA-13 cells, respectively. In addition, the data indicate that LPL interaction with heparan sulfate and the LRP pathways is independent of each other. The study shows that these cells possess both a heparan sulfate-dependent pathway and an LRP-dependent pathway for LPL metabolism and that the two pathways are independent of each other.

Alleles↗
PubMed1994

Ultrastructural observation on macrophage-lymphocyte interactions in semen from Tripterygium wilfordii Hook.f. takers.

Sixty-nine specimens from Tripterygium Wilfordii Hook.f. (TWH) users were investigated by electron microscopy. No macrophages were demonstrated in the 21 specimens collected prior to the administration of TWH. However, it was found in 23 out of the 48 semen specimens obtained following the TWH administration. The macrophages were functionally active as shown by the presence of a large number of cytoplasmic processes and pseudopodia on the surface, and primary and secondary lysosomes in the cytoplasm. The macrophages phagocytized sperm debris and degenerated or dead spermatids with formation of specific phagosomes. Around those macrophages, lymphocytes were commonly noted. The cytoplasmic processes of the two cell types could come into contact or even fuse with each other, leading to tight junction-like structure; in some of the contacts, the plasma membranes were found dissolved so as to form direct cytoplasmic linkage.

Adolescent↗